Coin-Tradiction by Roy Kueppers - Trick

A penny is shown to the spectator and rubbed with the thumb to generate heat on the coin. The hand then squeezes the penny to slightly bend it. Once again, the penny is rubbed to generate more heat to the coin. The coin is squeezed yet again and shown to be extremely bent. The Magician then uses the other open hand to rub and press the penny flat into its original shape.